The present invention relates to a tumble dryer and in this instance in particular a household tumble dryer according to the preamble of the independent claim.
A tumble dryer of this type is known from each of the previously published documents JP 09 056 996 A, EP 2 360 310 A1 and DE 38 09 754 A1. According to each of these documents a temperature-activated release facility for releasing extinguishing agent in the event of a fire is provided in each instance.
It can always happen with tumble dryers that certain small elements, for example lint or other impurities, for example dust from abraded drive belts, collects and is deposited in the interior of the tumble dryer, for example in the base region of the housing. When a certain temperature is reached, these elements could catch fire. This has to be prevented. In some regions corresponding test methods are already in force or will soon be in force to demonstrate that fire cannot exit from the tumble dryer. To this end, it will be verified for example in the US from 2013 that a cloth placed over the tumble dryer cannot ignite during the test.
Tumble dryer manufacturers are therefore keen to be able to offer tumble dryers in which fire can be actively extinguished in the interior of the tumble dryer or in which the fire can at least be prevented from exiting to the outside. To this end it is known for example from DE 10 2007 061 521 A1 that the fire can be actively controlled by extinguishing using water or other chemicals from a container disposed above the drum, once the extinguishing operation has been triggered by a temperature sensor. However such a solution generally requires a functioning power supply to operate the temperature sensor, the associated control technology and evaluation circuits and optionally also further facilities.
Alternatively it is also possible to control the fire passively by no longer using any readily combustible plastic parts, just fire-resistant plastics, metals or other materials. However this is only possible if higher production costs are accepted.
A fire extinguishing apparatus for tumble dryers according to the preamble of claim 1 is known from DE 38 09 754 A1. Disposed below the worktop is a container having a number of cells, in which an extinguishing agent is stored. Holes are provided on the lower faces of the cells, being closed off with the aid of a protective cover or destructible membrane and being destroyed in the presence of flames or at a temperature above a predefined limit temperature. When the limit temperature is reached, the extinguishing agent is therefore released and drops down to extinguish the occurring fire. According to one alternative embodiment a pressurized container of extinguishing agent is provided, from which lines lead to points considered to be at risk of fire. In the event of a fire or high temperature the lines can melt, thereby breaking or opening. This releases the extinguishing agent.
The tumble dryers known from the publications cited above however have the disadvantage that the extinguishing agent is only released at previously determined points and therefore a fire occurring at any random point may not be reliably extinguished.